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[74.98.231.160]) by smtp.gmail.com with ESMTPSA id 6a1803df08f44-6dfad85ffbasm8870066d6.15.2025.01.10.04.49.51 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Fri, 10 Jan 2025 04:49:51 -0800 (PST) Date: Fri, 10 Jan 2025 12:49:49 +0000 From: Kaiyang Zhao To: Li Zhijian Cc: linux-mm@kvack.org, Andrew Morton , linux-kernel@vger.kernel.org Subject: Re: [PATCH 1/2] mm/vmscan: Accumulate nr_demoted for accurate demotion statistics Message-ID: References: <20250110122133.423481-1-lizhijian@fujitsu.com> Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20250110122133.423481-1-lizhijian@fujitsu.com> On Fri, Jan 10, 2025 at 08:21:32PM +0800, Li Zhijian wrote: > In the shrink_folio_list() function, demote_folio_list() can be called > multiple times, which can lead to inaccurate demotion statistics if the > number of demoted pages is not accumulated correctly. It looks like demotion will only be attempted once. On the second pass, do_demote_pass will be false, demote_folios will be empty and demote_folio_list() will do nothing. But I guess there is no harm in making nr_demoted an accumulation for less confusion in the future...